Sumboodie
Thread starter
It's because a lithium battery is HAZMAT. It's allowed in carry on because a fire would be detected fairly quickly and could be put out, vs if it happens in cargo.I just shipped my son back to San Diego with a Milwaukee screw gun and impact. “No power tools” in carry on luggage but li ion batteries were fine. He got flagged at tsa and had to check the tools but had to carry the batteries in his backpack. Real brain trust stuff at work here.
Same with spare batteries for phone, laptops, etc. Supposed to be in carry on.